Aclosed system of mass 2 kg undergoes an adiabatic process. the work done on the system is 30 kj. the velocity of the system changes from 3 m/s to 15 m/s. during the process, the elevation of the system increases 45 meters. the acceleration of gravity is g -9.8 m/s2. determine the change in internal energy of the system in kj.

Amass of 1.5 kg of air at 120 kpa and 24°c is contained in a gas-tight, frictionless piston-cylinder device. the air is now compressed to a final pressure of 720 kpa. during the process, heat is transferred from the air such that the temperature inside the cylinder remains constant. calculate the boundary work input during this process.

Coiled springs ought to be very strong and stiff. si3n4 is a strong, stiff material. would you select this material for a spring? explain.

Acertain flow of air (at stp) has a velocity distribution given by v i (in ft/s). if this flow is going through a 4 ft square area in the yz-plane (centered at the origin), what is the mass flow rate (in lbm/s)?